Due to its characteristics of being easily applicable to various products and electrical properties such as a high energy density, a secondary battery is not only commonly applied to a portable device, but universally applied to an electric vehicle (EV), a hybrid vehicle (HV), or an energy storage system that run on an electrical driving source. This secondary battery is gaining attention for its primary advantage of remarkably reducing the use of fossil fuels and not generating by-products from the use of energy, making it a new eco-friendly and energy efficient source of energy.
A battery pack for use in electric vehicles has a structure consisting of a plurality of cell assemblies connected in series, each cell assembly including a plurality of unit cells, to obtain high power. Also, the unit cell includes a positive electrode current collector and a negative electrode current collector, a separator, an active material, and an electrolyte solution, and allows repeated charging and discharging by electrochemical reactions between the components.
In addition to this basic structure, the battery pack further includes a battery management unit (BMU) to monitor and control a state of a secondary battery by applying an algorithm for control of power supply to a driving load such as a motor, measurement of electrical characteristic values such as current or voltage, charge/discharge control, voltage equalization control, and state of charge (SOC) estimation.
The battery pack is mounted on a battery operating system including a load which is supplied with power from the battery pack, and supplies power to the load. In this instance, the battery management unit may be electrically connected to the battery operating system through a communication line. Also, the battery management unit receives a command related to management of the battery pack including charge and discharge of the secondary battery included in the battery pack through the communication line.
However, when an error occurs in a signal received by the battery management unit through the communication line, operation of the battery pack may go wrong. There are various causes of the error in the signal such as physical damage to the communication line, or a program error or external hacking in the battery operating system.
When an error occurs in the received signal, an accident may happen such as overcharge and over-discharge of the battery pack, so there is a need for a battery management unit for preventing an erroneous control algorithm from being run due to an error occurred in communication.